These studies are designed to define the immunologic mechanisms that may lead to ocular and specifically corneal pathology. Four different experimental systems will be employed. A model of autoimmune interstitial keratitis in the rabbit will be developed, the organ-specific antigens and the immunopathologic mechanisms involved will be identified, and the relationship to human corneal disease will be defined. The significance of the secretory immune system in the eye will be explored, in terms of mechanisms of activation and traffic among various secretory organs, in an attempt to define the origin and specificity of the cells involved in the ocular component of the secretory immune system. Studies on the mechanism of endothelial cell destruction during corneal graft rejection will continue, utilizing an intraocular graft-versus-host reaction in the rabbit eye, in order to define more precisely the conditions under which effector lymphocytes destroy corneal endothelial target cells. Finally, attempts will be made to adapt autologous macrophages/monocytes for use as replacement corneal endothelium in keratoplasty, an approach of potentially great clinical interest in transplantation.